copeman



May 1, 1928.

L. G. COPEMAN swoms: mom:

Filed udy 29, 1925 2 Sheets-Sheet 1 May 1, 1928. 1,667,721

L.G. COPEMAN STONE MOLD Filed May 29, 1925 2 Sheets-Shoot 2 j w JTO/YE JNVEN'I'OR:

. yc/ Tax/1mm AQZWZZZWM ATTORNEY.

Patented May 1, 1928.

UNITED STATES PATENT OFFICE.-

LLOYD G. COIBEMAN, OF FLINT, MICHIGAN, ASSIGNOR TO COPEMAN LABORATORIES COMPANY, OF FLINT, MICHIGAN, A CORPORATION OF MICHIGAN.

srom: morn.

Application filed May 29, 1925. Serial No. 88,649

to which cannot satisfactorily be stored forfuture reproductions of the pattern.

I have found that a mold section can be made of a composition employing about magnesium oxide, by weight,

l 16 finely ground silica, by'weight, and 50% 50-mesh silica sand, by weight, and to which is added suflicient chloride of magnesium in solution at 26 B. specific gravity to form a mix which may be readily poured, and that 20 the resulting artificial stone has the property of neither ex anding nor shrinking to any appreciable 'egree. This composition also solidifies into apermanent block of artificial stone having relatively great hard- 25 ness and resistance to wear, or fracture.

Of course a mold section made of a stone composition of this character, has utility wider than the molding of patterns. but it has its" chief value as I now see it fofthis I0 purpose, as it permits the reproduction of patterns that are very accurate replicas of the master pression in theplastie stone. as In reproducing a mold block such as I have described one may )roceed in several ways. For instance, if t e parting line of the patternis a straight one, one simply lays the flask section or drag on a flat surface, places the pattern in the flask and then 'pours" the com osition which I have described, over t e pattern. It may be desirable inorder to prevent the wooden pattern stickin in the stone to utilize a' stone pattern. T is can be easily done by first makin an'impression of the wooden pattern in a p aster cast and then casting a master pattern of this same stone mix in this plaster cast. This stone master pattern may then so'be used to form the impression in the permanentmold' block. It will be desirable,

however, before the pour is made into the flask to coat the stone attern with a parting material. It Wlll e found that such attern, such as thewoodenpattern which 15 first used to make the imnent stone block better than a wooden pattern. especially with the ordinary shellac coatings that are placed on these wooden patterns.

Where the pattern has an irregular part ing line, the same is placed in a flask resting on a fiat surface. and this is filled with sand with a suitablebinding mix. The sand mix is then packed in about the pattern up to the parting line. Then the stone mix already described is poured in on this sand to fill the flask. When this hardened it will be obvious that one has a permanent block of stone which is a pattern impression. The other stone block, to form the opposite side of the pattern, can be easily cast by utilizing this first stone block by setting it in a flask, greasing or oiling the surface with any suitable parting material, the pattern itself bemg supported in the impression in this block and being coated with a parting material. Thereupon the remainder of the flask is filled up with the same mix, and when. this is set one has a second artificial stone block with an impression of the other side of the pattern.

The molds may be coated with a very thin coating of waterproof material, or I may apply a thin coatlng of enamel, such for instance, as Duco or pyroxilin enamel.

I have illustrated the stone attern block which is shown in its completed state in Fig. 1. In Fig. 2 the flask containing half the pattern, which has a straight parting line, is shown.

Fig. 3 shows the flask filled with the mix, which is allowed to set.

Fig. 4 shows the flask containing a pattern which has an irregular arting line and which is packed with sand.

Fig. 5*shows this sand flask with the stone poured in to form the mold block having the irregular parting line.

Fig. 6 shows the flask in which the first cast mold block, together with the pattern, 100 is utilized to form the second mold block of stone. Fig. 7 is a cross section taken on'the line 77 of Fig. 6, with the pattern removed, showing the molds slightly separated. 105

What I claim is:

1. A, permanent mold block for re roducing patterns, vcomprisingjan arti cial stone block composed of eementitious com- Ill u a, stone pattern separates from the permaposition employmg silica, magnesium oxide, 1

least a. portion of the and magnesium chloride, and in which is contained a permanent impression of at atternto be cast. 2. A permanent mol section for casting and reproducing patterns, comprising a solid block of composition material containing substantially of magnesium oxide, of finely ground silica by Wei ht, 50% ofsilica sand by Weight, mixed wit 1- a solution of magncsilun chloride, said block when hardened containing a permanent impression of a portion of a pattern.

3. A composition for making mold blocks comprising substantially 20% of magnesium oxide, 30% of silica, and 50% of silica sand mixed with a solution of magnesium chloride to the desired consistency.

20 ing a blockof artificial 4. A permanent mold block for reproduc-' ing patterns of a plastic material, comprisstone containing a permanent impression of at least a portion Qof the article to be. reproduced, said artificial stone being of a hard cementitious material of sufiicient compressive strength to withstand the molding and removing of-patterns and handling without chipping or breaking, whereby the same may be used for reproducing patterns at anytime. V

5. Acomposition for making mold blocks comprising substantially 20% of magnesium oxide, 30% of finelyground silica, and 50% of 5()- meslrsilica sand mixed with a solution of magnesium chloride in sufficient amount to give the desired consistency.

6. A composition for making mold blocks com rising substantially 20% of magnesium .oxix e, 30% offinely ground silica, and 50% of silica sand mixed to the desired consisten'cy with a solution of magnesium chloride, v 40 having a specific gravity of 26 B; v In testimony whereof I hav afii'xed my signature.

LLOYD G. coPEMAiv; 

